1. Field of the Invention
This invention relates to an image recording apparatus in which high-frequency waves are applied at a fixing station in the image formation process of a copying apparatus or an information recording apparatus to thereby fix a visualized image on a recording medium and record the image.
2. Description of the Prior Art
A heating-fixing method using high-frequency waves such as microwaves and a device therefor have already been disclosed in Japanese Patent Publication No. 38171/1974, Japanese Laid-open Patent Application No. 20039/1977 and Japanese Patent Publication No. 10865/1979. This high-frequency wave heating-fixing device is an excellent one which has eliminated the following disadvantages in the so-called extraneous heating and fixation. That is, it is a compact a device which reduces the wait time until a temperature necessary for fixation is reached, which eliminates the danger of fire or the like occuring when a recording medium such as paper stays within the fixing area by some cause or other, and which prevents creation of wrinkles and disturbance of image which would otherwise result from the contact of the recording medium with a heating roller or the like.
However, the use of a high-frequency waves makes it necessary to take sufficient care of leakage of the high-frequency waves, whereas means for solving such a problem has not been provided in any image formation apparatus.
When such a high-frequency wave heating-fixing device is employed as the fixing device in an image formation apparatus such as an electrophotographic copying apparatus or other information recording apparatus, there occurs a disadvantage or inconvenience that high-frequency waves may leak to the outside of the fixing device and further to the outside of the copying apparatus or the recording apparatus. Typical of such inconvenience are the creation of noise in an IC mechanism provided in a multistage tray or other instrument disposed outside the image formation apparatus and the influence imparted to humans. Also, in the image formation apparatus, there may be conceived a case where the high-frequency waves imparted from an inadvertent portion to an optical system member designed to impart a predetermined exposure amount to thereby disturb the distribution of light or a case where an unnecessary magnetic field or the like is created due to leakage of high-frequency waves to thereby adversely affect the image formation process.
In any case, preventing unnecessary leakage of high-frequency waves is necessary for maintaining the stability of the predetermined image formation.